Manufacture of waterproof tubing from cellulose pulp



M. O. SCHUR April 19, 1932.

MANUFACTURE OF WATERPROOF TUBING FROM CELLULOSE PULP Filed Sept. 28, 1929 bular form,

Patented Apr. 19, 1932 UNITED STATES PATENT OFFICE MILTON O. SCHUR, 0F BERLIN, NEW HAMPSHIRE, ASSIGNOR '10 BERLIN, NEW HAMPSHIRE, A CORPORATION OF BROWN COIPAHY, OI

MAINE MANUFACTURE OF WATERPROOF TUBING FROM CELLULOSE PULP Application filed September 28, 1929. Serial No. 895,881.

This invention relates to the manufacture of multi-ply pulp products, and more particularly to those formed by winding into tubular form a wet web of cellulose pulp produced on machinery of the paper-making type. In the manufacture of such products, it is desired to effect a thorough matting together or interlocking of the successive layers in order to avoid separation of the layers during or after drying. When such products are to be impregnated after drying with liquid waterproofing agents such as molten pitch, it is further desired to produce a product of sufiicient porosity to permit such agents to penetrate therethrough in large amount with rapidity and uniformity.

In accordance with the method of my invention the web of wet ulp is roughened on both its surfaces before being wound into tuas I have found that not only is a better interlockingefl'ected between the superposed layers, but the resulting product when dried is more porous and may be impregnated more rapidly and more perfectly than heretofore. While my method may be applied to advanta e when the web is formed on various types 0% papermaking machines, it is especial y pertinent to webs formed on so-called cylinder machines. I have observed that the wet web as usually removed from the cylinder mould by the carrier felt and then wound on a mandrel or make-up roll, is roughened sufliciently for the purposes of m method, on one face, by contact with the fe t, but is smooth on its opposite face, where the effect of surface tension on the water associated with the pul is to lay down the fibers. It is hence a simp e and inex ensive matter to practice my method on sue a web, as all that need be done is to rougher. the outer surface of the web being carried by the felt, to undo the smoothing effect of surface tension. This may be carried so far as to break up sheet formation, although all that is usua ly necessary is to produce a fuzzy or rough surface. Heretofore in the winding operation, a rough web surface has been superposed on a comparatively smooth web surface, with the result that interlocking of the successive layers was apt to be impe ect, unless special measures were taken, such as depositing an adhesive, e. g., elatinized cellulose, on the web surface, or eating the pul to a high degree to ensure the presence of suicient gelatinized cellulose in the wet web to effect good bonding between the layers. When the multiply product contains considerable gelatinized cellulose, however, it is dense and diflicult to impregnate, and if removed from a mandrel in tubular form and dried in such form, drying must be carried out very slowly, in order to avoid warping.

While not limited thereto, my method makes possible the realization of most significant advantages in manufacturing of tubes to be impregnated with waterproofing material such as molten pitch and intended for use as in housing underground electric cables or for conducting aqueous liquids. I have found that the method of my invention makes possible the production of tubes the laminae of which are more perfectly matted together and which absorb during impregnation more pitch and in a shorter eriod 0 time. This increased absorption 0 pitch is most desirable, since if moisture gains access to the interior of the tube wall, there is a tendency towards swelling and se aration of the lam inae. My method may a so be used to advantage when making multi-ply boards or sheets on a cylinder machine by winding a wet web on a make-upv roll, and then strip ing the pulp in sheet form from the roll, t e slieet then being dried and, if desired, impregnated with a suitable agent.

With these and other objects and features in view, my invention may best be understood from the following more complete description thereof, when considered in conjunction with the accompan lustrate my metho as ap lied to the manufacture of tubes on a cylinder machine.

Figure 1 represents more or less diagrammatically and conventionally a side elevation of a machine for carrying out my method.

Fi re 2 shows roug ening the outer sur ace of the web.

Figure 3 is an enlarged fra entary section through the winding end o iihe machine.

Figure 4 is an enlargement of a portion of ing drawings, which ilin perspective means for Figure 3, to show the roughness .of the surend of a horizontal shaft 17 journaled in a faces of the web being wound. bearing 18 afforded by the bracket 14. The

Referring to Figure 1 of the drawings, 1 other end of the shaft 17 passes through the indicates a vat into which a suspension bearing 18 and,as shown, terminatesinadisk pulp beaten to the desired degree and at a member 19. Fixed eccentrically to the disk 7 consistency suitable for forming into a web 19 is a pin 20 on which is loosely enga d one may be delivered. Rotating partially suband 21 of a crank 22, the other en 23 of merged in the pulp suspension, is a cylinder which is provided on each side with a pin 24 mould 2, on which the pulp deposits as alayer loosely enga ing fork members 25 formed 3, which is carried out of the pulp suspension at one end 0 the rod 9. The rod 9 may be 7 into contact with a felt 4. The layer of pulp guided in its oscillatory movement by a bearis picked up from the cylinder mould by the ing member 26 carried by an arm 2 extendfelt under the action of sufficient pressure ing from the bearing member 18. It will exerted by a couch roll 5. The web of pulp thus be seen that, as the couch roll rotates,

contains considerable water at this stage, and the shafts 12 and 17 are caused to rotate, the is quite fragile. In order to avoid breaking crank 22 converting the rotary movement of during subsequent winding, it should be parthe shaft 17 into an oscillating movement and tially dewatered, this being accomplished, as causing the rod 9 to oscillate, carrying the shown, by passing the wet web while supstrips 7 to and fro transversely of the web.

ported by the felt over a suction box 6. The The felt 4 as shown carries the web to a 85 passage of the freshly formed pulp matter rotary mandrel 28 above a pair of rolls 29,

out o the pool in the cy 'nder vat causes the which support and guide the felt as the web outer fibers to lay down through the action is being wound on the mandrel, as shown in of surface tension, and a smoot slimy-feel- Figures 3 and 4. The felt is then assed ing surface results on the pulp mat. In acdownwardly under a guide roll 30 an is re- 90 cordance with the present invention I may turned to the cylinder mould 3, from which it nullify this effect by rougltfning the surface picks up the layer of pulp continuously beof the mat before, on, or a rthe suction box. in deposited on the mould.

It is an interesting fact that the beneficial en the desired thickness of tube wall 30 results realized b roughening the sheet perhas been attained, the mandrel supporting the 9 sist even though e pulp web asses over one wet tube ma be transferred to a dryer snot or more suction boxes after t e roughening shown) and e replaced by another man rel. means have been applied. Any suitable The tubes may be delivered into the dryer, roughening means, such as brushes or combs, which may be of the type described in Patma be employed, but I have found it exent No. 1,697,454, issued Janna 1, 1929, to pedient to use a series of felt strips 7 for this Orton B. Brown and Howard Par er,where p The strips may be supported, as they are initially subjected to a high humidshown in Figures 1 and 3, above the machine ity at relatively high temperature, say, about and transversely of the web, the lower ends 50% humidity at 150 F., and are supported of the strips being permitted to drag over on conveyors, consisting of closely spaced, the web be ore it passes over the suction box. uniformly rotated rolls. As the tubes as- A series of felt strips constitutes a flexible arsume the wet-bulb temperature, the become rangement which produces the desired somewhat plastic, and under the in uence of roughening effect wit out so breaking up the the rolling they expand a trifle, so that after,

web as to prevent the production 0 a tube say, two or three hours, the mandrels may no of substantially uniform thickness throughbe withdrawn and the wet tubes allowed to out. The strips may be freely hung from proceed through the dryer free to dry from suitable supports 8, fixedto arod9 extending the inside as well as from the outside. In transversely of the web. The rod is preferfrom eighteen to thirty-six hours, depending ably osclllated transversely of the web to upon the thickness of the tube wall and upon cause a to-and-fro movement of the strips the size of the tube, the tubes reach the end while they are dragging over the web, thereof the dryer, containing less than 2% moisbg ensuring a rou henmg of substantlally ture on a bone-dry basis, and may now be t e entire web s ace. Oscillatory moveimpregnated with pitch, which renders them ment may be imparted to the rod 9 by any water-resistant. suitable means, or instance, by means ac- While my method has been described in tuated by the rotation of the couch roll 5. connection with the manufacture of tubes As shown 1n Figures 1 and 2, such means usingv papermaking machinery of the cylinmay comprise a gear 10 fixed at one end of der type, it is to be understood that it may the couch roll and meshing with a gear 11 find'application in the manufacture of other fixed to the lower end of a vertical shaft 12, multi-ply products, for instance, multi-ply' which is 'ournaled in a bearing 13 afforded sheet material, the wet web being formed on by a brac et 14. The upper on of the shaft other types of paper machines.

12 above the bead 13 is provided with a I claim:

v gear 15 meshing wi a gear 16 fixed to one 7 In the production of waterproof tubing from cellulose pulp, the combination of steps which comprises progressively forming a wet web of pulp on a cylinder mold, pro essively' picking up said web on a carrier elt from said mold, rou hening the outer surface of said web while ing carried by said felt, removing the roughened web from said felt and simultaneously convoluting it into tubular form, dryin the convoluted tube, and impregnating t e dried tube with a water roofin agent of the nature of molten pitc n testimony whereof I have aflixed my signature.

MImTON O. SCHUR. 

